The invention relates to improvements in electrostatic spray guns, and more particularly to improvements in portable (hand-held) spray guns which can be used for spraying liquid and/or flowable solid materials, particularly pulverulent materials.
It is known to provide a hand-held electrostatic spray gun with a body having a grip adapted to be held by hand and supporting a trigger. A second portion of the body carries a barrel serving to receive material to be sprayed from an inlet which is provided on the body of the spray gun ahead of the trigger. It is further known to install the high-voltage generator of the spray gun in the body, particularly in the grip, and to provide the generator with at least one high-voltage electrode.
A spray gun of the above outlined character is disclosed in published European patent application No. 0 157 199. The entire high-voltage generator (the details of which are not disclosed) is installed in the grip and the generator has a plastic housing which resembles a grip. The rear side of the grip is formed with an air admitting inlet, and the grip further defines a portion of the air channel which leads to the barrel. The inlet for the material to be sprayed is provided at the front end of the body immediately behind the location where the barrel can be detached from the body. The connection between the barrel and the body comprises mating internal and external threads. The barrel is formed with a centrally located paint channel and with three additional channels which surround the paint channel and are spaced apart relative to each other at angles of 120 degrees. One of the additional channels supplies atomizer air, another additional channel supplies control air, and the third additional channel accommodates a high-voltage cable leading to a sprayer electrode.
The object of the invention which is disclosed in the published European patent application is to move the center of gravity as far back as possible in order to reduce the effort which is required to properly hold the grip for an extended interval of time. A drawback of such proposal is that the high-voltage generator must employ a number of highly miniaturized components with attendant reduction of its output. Moreover, the housing of the high-voltage generator occupies by far the major part of the grip. Thus, if the high-voltage generator must be relatively large or if the grip is to accommodate one or more additional parts of the spray gun, the dimensions of the grip must be unduly increased so that such bulky grip cannot be properly held by a hand of the operator.